Speciation of Methyl- and Inorganic Mercury in Biological Tissues Using Ethylation and Gas Chromatography With Furnace Atomization Plasma Emission Spectrometric Detection

Abstract

A sensitive and interference-free method for the quantification of inorganic and methylmercury species in biological tissues is presented using purge-and-trap injection–GC–AES. Samples were solubilized with tetramethylammonium hydroxide and the ionic species were purged from aqueous solution after ethylation with sodium tetraethylborate. The species were preconcentrated on Tenax-TA and thermally desorbed onto an isothermal (90 °C) GC column packed with 15% OV-3 on Chromasorb W. The separated species were eluted in He to a FAPES source for detection by AES at 253.6 nm. Absolute detection limits of 1 and 7 pg for inorganic and methylmercury, respectively, can be obtained, corresponding to concentration LODs of 0.2 and 1.4 ng g ^-1 , respectively, in solid tissue samples. Precision of determination is better than 10% RSD. The accuracy of the technique was validated by the analysis of National Research Council of Canada CRMs DORM-2, DOLT-2 and TORT-2, certified for mercury species content.